ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/jsr166/jsr166/src/main/java/util/PriorityQueue.java
(Generate patch)

Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.72 by jsr166, Fri Jun 10 00:20:44 2011 UTC vs.
Revision 1.84 by jsr166, Sat Jan 19 18:11:56 2013 UTC

# Line 1 | Line 1
1   /*
2 < * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
2 > * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
3   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4   *
5   * This code is free software; you can redistribute it and/or modify it
6   * under the terms of the GNU General Public License version 2 only, as
7 < * published by the Free Software Foundation.  Sun designates this
7 > * published by the Free Software Foundation.  Oracle designates this
8   * particular file as subject to the "Classpath" exception as provided
9 < * by Sun in the LICENSE file that accompanied this code.
9 > * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# Line 24 | Line 24
24   */
25  
26   package java.util;
27 + import java.util.stream.Stream;
28 + import java.util.Spliterator;
29 + import java.util.stream.Streams;
30 + import java.util.function.Block;
31  
32   /**
33   * An unbounded priority {@linkplain Queue queue} based on a priority heap.
# Line 56 | Line 60 | package java.util;
60   * the priority queue in any particular order. If you need ordered
61   * traversal, consider using {@code Arrays.sort(pq.toArray())}.
62   *
63 < * <p> <strong>Note that this implementation is not synchronized.</strong>
63 > * <p><strong>Note that this implementation is not synchronized.</strong>
64   * Multiple threads should not access a {@code PriorityQueue}
65   * instance concurrently if any of the threads modifies the queue.
66   * Instead, use the thread-safe {@link
# Line 92 | Line 96 | public class PriorityQueue<E> extends Ab
96       * heap and each descendant d of n, n <= d.  The element with the
97       * lowest value is in queue[0], assuming the queue is nonempty.
98       */
99 <    private transient Object[] queue;
99 >    transient Object[] queue; // non-private to simplify nested class access
100  
101      /**
102       * The number of elements in the priority queue.
# Line 109 | Line 113 | public class PriorityQueue<E> extends Ab
113       * The number of times this priority queue has been
114       * <i>structurally modified</i>.  See AbstractList for gory details.
115       */
116 <    private transient int modCount = 0;
116 >    transient int modCount = 0; // non-private to simplify nested class access
117  
118      /**
119       * Creates a {@code PriorityQueue} with the default initial
# Line 330 | Line 334 | public class PriorityQueue<E> extends Ab
334          return true;
335      }
336  
337 +    @SuppressWarnings("unchecked")
338      public E peek() {
339 <        if (size == 0)
335 <            return null;
336 <        return (E) queue[0];
339 >        return (size == 0) ? null : (E) queue[0];
340      }
341  
342      private int indexOf(Object o) {
# Line 430 | Line 433 | public class PriorityQueue<E> extends Ab
433       * precise control over the runtime type of the output array, and may,
434       * under certain circumstances, be used to save allocation costs.
435       *
436 <     * <p>Suppose <tt>x</tt> is a queue known to contain only strings.
436 >     * <p>Suppose {@code x} is a queue known to contain only strings.
437       * The following code can be used to dump the queue into a newly
438 <     * allocated array of <tt>String</tt>:
438 >     * allocated array of {@code String}:
439       *
440       *  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
441       *
442 <     * Note that <tt>toArray(new Object[0])</tt> is identical in function to
443 <     * <tt>toArray()</tt>.
442 >     * Note that {@code toArray(new Object[0])} is identical in function to
443 >     * {@code toArray()}.
444       *
445       * @param a the array into which the elements of the queue are to
446       *          be stored, if it is big enough; otherwise, a new array of the
# Line 448 | Line 451 | public class PriorityQueue<E> extends Ab
451       *         this queue
452       * @throws NullPointerException if the specified array is null
453       */
454 +    @SuppressWarnings("unchecked")
455      public <T> T[] toArray(T[] a) {
456          if (a.length < size)
457              // Make a new array of a's runtime type, but my contents:
# Line 513 | Line 517 | public class PriorityQueue<E> extends Ab
517                  (forgetMeNot != null && !forgetMeNot.isEmpty());
518          }
519  
520 +        @SuppressWarnings("unchecked")
521          public E next() {
522              if (expectedModCount != modCount)
523                  throw new ConcurrentModificationException();
# Line 565 | Line 570 | public class PriorityQueue<E> extends Ab
570          size = 0;
571      }
572  
573 +    @SuppressWarnings("unchecked")
574      public E poll() {
575          if (size == 0)
576              return null;
# Line 590 | Line 596 | public class PriorityQueue<E> extends Ab
596       * position before i. This fact is used by iterator.remove so as to
597       * avoid missing traversing elements.
598       */
599 +    @SuppressWarnings("unchecked")
600      private E removeAt(int i) {
601 <        assert i >= 0 && i < size;
601 >        // assert i >= 0 && i < size;
602          modCount++;
603          int s = --size;
604          if (s == i) // removed last element
# Line 628 | Line 635 | public class PriorityQueue<E> extends Ab
635              siftUpComparable(k, x);
636      }
637  
638 +    @SuppressWarnings("unchecked")
639      private void siftUpComparable(int k, E x) {
640          Comparable<? super E> key = (Comparable<? super E>) x;
641          while (k > 0) {
# Line 641 | Line 649 | public class PriorityQueue<E> extends Ab
649          queue[k] = key;
650      }
651  
652 +    @SuppressWarnings("unchecked")
653      private void siftUpUsingComparator(int k, E x) {
654          while (k > 0) {
655              int parent = (k - 1) >>> 1;
# Line 668 | Line 677 | public class PriorityQueue<E> extends Ab
677              siftDownComparable(k, x);
678      }
679  
680 +    @SuppressWarnings("unchecked")
681      private void siftDownComparable(int k, E x) {
682          Comparable<? super E> key = (Comparable<? super E>)x;
683          int half = size >>> 1;        // loop while a non-leaf
# Line 686 | Line 696 | public class PriorityQueue<E> extends Ab
696          queue[k] = key;
697      }
698  
699 +    @SuppressWarnings("unchecked")
700      private void siftDownUsingComparator(int k, E x) {
701          int half = size >>> 1;
702          while (k < half) {
# Line 707 | Line 718 | public class PriorityQueue<E> extends Ab
718       * Establishes the heap invariant (described above) in the entire tree,
719       * assuming nothing about the order of the elements prior to the call.
720       */
721 +    @SuppressWarnings("unchecked")
722      private void heapify() {
723          for (int i = (size >>> 1) - 1; i >= 0; i--)
724              siftDown(i, (E) queue[i]);
# Line 726 | Line 738 | public class PriorityQueue<E> extends Ab
738      }
739  
740      /**
741 <     * Saves the state of the instance to a stream (that
730 <     * is, serializes it).
741 >     * Saves this queue to a stream (that is, serializes it).
742       *
743       * @serialData The length of the array backing the instance is
744       *             emitted (int), followed by all of its elements
# Line 735 | Line 746 | public class PriorityQueue<E> extends Ab
746       * @param s the stream
747       */
748      private void writeObject(java.io.ObjectOutputStream s)
749 <        throws java.io.IOException{
749 >        throws java.io.IOException {
750          // Write out element count, and any hidden stuff
751          s.defaultWriteObject();
752  
# Line 771 | Line 782 | public class PriorityQueue<E> extends Ab
782          // spec has never explained what that might be.
783          heapify();
784      }
785 +
786 +    // wrapping constructor in method avoids transient javac problems
787 +    final PriorityQueueSpliterator<E> spliterator(int origin, int fence,
788 +                                                  int expectedModCount) {
789 +        return new PriorityQueueSpliterator<E>(this, origin, fence,
790 +                                               expectedModCount);
791 +    }
792 +
793 +    public Stream<E> stream() {
794 +        int flags = Streams.STREAM_IS_SIZED;
795 +        return Streams.stream
796 +            (() -> spliterator(0, size, modCount), flags);
797 +    }
798 +    public Stream<E> parallelStream() {
799 +        int flags = Streams.STREAM_IS_SIZED;
800 +        return Streams.parallelStream
801 +            (() -> spliterator(0, size, modCount), flags);
802 +    }
803 +
804 +    /** Index-based split-by-two Spliterator */
805 +    static final class PriorityQueueSpliterator<E>
806 +        implements Spliterator<E>, Iterator<E> {
807 +        private final PriorityQueue<E> pq;
808 +        private int index;           // current index, modified on advance/split
809 +        private final int fence;     // one past last index
810 +        private final int expectedModCount; // for comodification checks
811 +
812 +        /** Create new spliterator covering the given  range */
813 +        PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
814 +                             int expectedModCount) {
815 +            this.pq = pq; this.index = origin; this.fence = fence;
816 +            this.expectedModCount = expectedModCount;
817 +        }
818 +
819 +        public PriorityQueueSpliterator<E> trySplit() {
820 +            int lo = index, mid = (lo + fence) >>> 1;
821 +            return (lo >= mid) ? null :
822 +                new PriorityQueueSpliterator<E>(pq, lo, index = mid,
823 +                                            expectedModCount);
824 +        }
825 +
826 +        public void forEach(Block<? super E> block) {
827 +            Object[] a; int i, hi; // hoist accesses and checks from loop
828 +            if (block == null)
829 +                throw new NullPointerException();
830 +            if ((a = pq.queue).length >= (hi = fence) &&
831 +                (i = index) >= 0 && i < hi) {
832 +                index = hi;
833 +                do {
834 +                    @SuppressWarnings("unchecked") E e = (E) a[i];
835 +                    block.accept(e);
836 +                } while (++i < hi);
837 +                if (pq.modCount != expectedModCount)
838 +                    throw new ConcurrentModificationException();
839 +            }
840 +        }
841 +
842 +        public boolean tryAdvance(Block<? super E> block) {
843 +            if (index >= 0 && index < fence) {
844 +                if (pq.modCount != expectedModCount)
845 +                    throw new ConcurrentModificationException();
846 +                @SuppressWarnings("unchecked") E e =
847 +                    (E)pq.queue[index++];
848 +                block.accept(e);
849 +                return true;
850 +            }
851 +            return false;
852 +        }
853 +
854 +        public long estimateSize() { return (long)(fence - index); }
855 +        public boolean hasExactSize() { return true; }
856 +        public boolean hasExactSplits() { return true; }
857 +
858 +        // Iterator support
859 +        public Iterator<E> iterator() { return this; }
860 +        public void remove() { throw new UnsupportedOperationException(); }
861 +        public boolean hasNext() { return index >= 0 && index < fence; }
862 +
863 +        public E next() {
864 +            if (index < 0 || index >= fence)
865 +                throw new NoSuchElementException();
866 +            if (pq.modCount != expectedModCount)
867 +                throw new ConcurrentModificationException();
868 +            @SuppressWarnings("unchecked") E e =
869 +                (E) pq.queue[index++];
870 +            return e;
871 +        }
872 +    }
873   }

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines